Stippled Glass

Stippling: (1) The technique of tapping the surface of a glass object with a pointed tool, often with a diamond or tungsten-carbide tip. Each tap produces a mark, and the decoration is composed of many hundreds or thousands of marks. (2) On lacy-pattern pressed glass, the stippling is part of the decoration of the mold.

Source: Glass: A Pocket Dictionary of Terms Commonly Used to Describe Glass and Glassmaking compiled by David Whitehouse of The Corning Musueum of Glass.